1. Field of the Invention
The present invention is generally concerned with clutch release bearings, in particular those for automobile vehicles.
It is more particularly directed to a clutch release bearing of the so-called "pull" type designed to act in traction on the clutch release device of a clutch to be operated, for example the ends of fingers of a diaphragm spring.
The problem in this instance is that, although necessary disposed for the main part outside the clutch, the clutch release bearing must nevertheless be able to act within the latter, on the inside surface of the clutch release device, so as to be capable of exerting traction on it.
2. Description of the Prior Art
In some clutch release bearing assemblies, and in particular in the clutch release bearing assembly described in commonly assigned U.S. patent application Ser. No. 683,390 of Dec. 19, 1984, now U.S. Pat. No. 4,648,499 granted Mar. 10, 1987, it has been proposed to use between the clutch release bearing and the clutch release device to be operated a part referred to as the coupling part which, appropriately attached to the clutch release device, comprises on the side of the latter opposite the clutch release bearing a radial bearing flange through which it is adapted to operate on it, in cooperation with fastening means operative in traction between a coupling part of this kind and a part referred to as the drive part forming part of the clutch release bearing, adapted to provide an axial coupling between said parts in the axial direction from the clutch release device to the clutch release bearing.
In the aforementioned U.S. patent application the fastening means operative in traction generally comprise a coupling member that is elastically deformable in the radial direction, carried by one of the parts to be fastened together in traction, and designed to cooperate abutment fashion with a generally transverse drive bearing surface provided for this purpose on the other part.
A particular advantage of an arrangement such as this is that it enables the clutch release device of the clutch to be operated to be fitted with the coupling part in advance, even before the corresponding clutch cover assembly is put together, and then, at the final assembly stage, the attachment of the clutch release bearing to the coupling part by means of a simple clipping action.
In some of the embodiments described in the aforementioned U.S. patent application the coupling member is an annular ring referred to as the coupling ring which is at least partially engaged radially in an annular retaining groove formed for it on one of the parts to be fastened together in traction, the other of these parts comprising the drive bearing surface with which it has to cooperate to procure such fastening together in traction.
By virtue of this arrangement of the coupling member, all that is necessary is to insert the clutch release bearing axially into the central opening in the clutch release device of the clutch cover assembly: during such insertion, the coupling ring retracts elastically and, subsequently resuming its initial configuration between the bearing surfaces with which it is to cooperate, it ensures the necessary axial coupling between the clutch release bearing and the coupling part.
From this point of view, an arrangement of this kind is satisfactory.
Nevertheless, there may arise the problem of possible uncoupling of the clutch release bearing with respect to the clutch cover assembly, in order to change it, for example.
In one solution proposed in the aforementioned U.S. patent application, a part referred to as the decoupling part is mounted so as to be slidable axially on the drive part of the release bearing, from which it is separate, and like the drive part it also forms part of the clutch release bearing.
In practice, to permit uncoupling of the release bearing the decoupling part comprises an inclined flank forming one of the flanks of the groove in which the coupling ring is at least partially engaged, the other of the flanks being carried by the drive part, and a radial flange projecting from the edge of the decoupling part.
The flange features an axial flank on the side opposite the clutch release device and forms, at a distance from the clutch release bearing, to be more precise from the ball bearing of the latter, a shoulder adapted for manual actuation of any form of maneuvering member on the decoupling part.
Using any form of maneuvering member, such as a screwdriver, for example, on the decoupling part and more specifically on the shoulder of the flange of the decoupling part, the decoupling part is pushed back in the axial direction towards the coupling ring, the maneuvering member bearing against the cover of the release bearing, for example, to be more precise on an upstanding edge of the cover.
The inclined flank of the decoupling part, forming one flank of the groove in which the coupling ring is disposed, pushes this ring radially out of the groove as it slides axially and thus enables the clutch release bearing to be disengaged by simply withdrawing it.
This device, although entirely satisfactory, makes use of a bearing flange that does not have any bush passing through the clutch release device. If it is required to use a bearing flange with a bush passing through the clutch release device, a solution entailing a decoupling part carrying a Belleville washer bearing on the clutch release device is not suitable, in particular for achieving proper decoupling, as it causes an increase in the overall axial size.
An object of the present invention is to alleviate these disadvantages and to create an arrangement with provision for decoupling using a coupling part with a bearing flange and an axial bush passing through the clutch release device and a decoupling part without any Belleville washer disposed between the decoupling part and the edge of the bush, whilst also providing other advantages.